CN203858351U - High-precision detection device of magnetic resonance signal of cesium optical pump - Google Patents
High-precision detection device of magnetic resonance signal of cesium optical pump Download PDFInfo
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- CN203858351U CN203858351U CN201320737198.2U CN201320737198U CN203858351U CN 203858351 U CN203858351 U CN 203858351U CN 201320737198 U CN201320737198 U CN 201320737198U CN 203858351 U CN203858351 U CN 203858351U
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Abstract
The utility model relates to a high-precision detection device of a magnetic resonance signal of a cesium optical pump. The high-precision detection device is composed of a signal shaping circuit, a mixer circuit, a single-chip microcomputer, a liquid crystal display circuit, frequency meters formed by CPLDs and a digital frequency synthesizer. An inputted to-be-detected cesium optical pump magnetic resonance signal is shaped by an amplitude-limiting amplification circuit; one frequency meter carries out rough detection to obtain a frequency value with an error less than 10HZ; truncation processing with over one thousand of bits is carried out on the value by the single-chip microcomputer so as to obtain a frequency value with over one thousand of bits; a frequency control word is calculated and is sent to a DDS formed by the CPLD to generate a sinusoidal wave signal corresponding to the frequency value; after processing by a 10-frequency doubling circuit, frequency mixing with a 10-frequency doubling original detected signal is carried out; a frequency difference signal is obtained by low-pass filtering; shaping is carried out on the signal and then precise measurement is carried out by another frequency meter; an actual frequency difference is obtained based on processing by the single-chip microcomputer; and the frequency difference is added to the obtained thousand-bit frequency to obtain the high-precision frequency value corresponding to the cesium optical pump magnetic resonance signal.
Description
Technical field
The utility model belongs to the frequency measurement field of high precision optical magnetic resonance signal, be specifically related to a kind of high precision testing circuit of caesium pumped magnetic resonance signal, can realize the accurate measurement to the optical magnetic resonance signal frequency in magnetic detection system a little less than caesium optical pumping, for Weak magentic-field measurement establish technical foundation.
Background technology
The weak magnetic detection system of caesium optical pumping is a kind of equipment that can accurately measure Weak magentic-field, can be widely used in the magnetic-field measurement field in productive life.The principle of this device measuring low-intensity magnetic field is the frequency by measuring optical magnetic resonance signal, then obtains final magnetic-field measurement result by correlation computations.So can frequency that precise measuring magnetic resonance signal most important to the measuring accuracy of whole equipment.
Traditional frequency measuring equipment, its frequency measurement accuracy and measurement range are very limited, response time is longer, cannot meet the frequency measurement requirement to the optical magnetic resonance signal in magnetic detection system a little less than caesium optical pumping, become the urgent problem solving of needs so develop a kind of accurately checkout equipment of this optical magnetic resonance signal frequency of measurement that is applicable to, also the accurate measurement of the adjustment to signal and frequency is had higher requirement.Therefore, must develop one and have compared with wide-measuring range, compared with high measurement accuracy with compared with the high-precision detection device that can be used for caesium pumped magnetic resonance signal of short response time.
The utility model solves the technical scheme that its technical matters adopts:
In order effectively to improve measuring accuracy and the measurement range to caesium optical magnetic resonance signal, the utility model has adopted has used Measuring Frequency Method and measuring period method to combine, give full play to the advantage of measuring separately, and in conjunction with mixing, adopt the measurement scheme of the measure such as rubidium atomic clock source and shielding of high stability.This device is mainly by high stability rubidium atomic clock, signal transformation circuit, low-pass filter, and mixting circuit, single chip machine controlling circuit, liquid crystal display circuit, the frequency meter and the digital frequency synthesizer etc. that are made up of CPLD form.Frequency meter 1 based on Measuring Frequency Method is mainly realized the bigness scale to caesium optical magnetic resonance signal, and frequency meter 2 based on measuring period method is mainly realized the accurate measurement to difference frequency signal, the two carries out data processing by single-chip microcomputer again, just can obtain accurate optical magnetic resonance signal frequency value.
After system powers on, first the frequency meter 1 bigness scale caesium optical magnetic resonance signal being formed by CPLD, obtaining an error is that 10Hz is with interior frequency values, issue MSP430 single-chip microcomputer by SPI mode, single-chip microcomputer is processed these data, obtain the required frequency control word of generation DDS corresponding to frequency values more than kilobit, again this control word is issued to CPLD, when CPLD receives after frequency control word, it produces corresponding sinusoidal wave and measured signal mixing, finally obtain difference frequency through low-pass filtering and amplification shaping, accurately measure difference frequency by the frequency meter 2 based on measuring period method again, then this measurement result mails to single-chip microcomputer, processing by single-chip microcomputer just can obtain final Measurement accuracy result.
The utility model compared with prior art has advantages of following main:
1. measurement mechanism combines Measuring Frequency Method and measuring period method, give full play to advantage separately, both effectively improve the precision of measuring and also there is wider measurement range, there is again certain reaction velocity simultaneously, can realize the continuous Measurement accuracy to signal, be suitable for very much the measurement of caesium optical magnetic resonance signal.
2. measurement mechanism adopts the work clock of rubidium atomic clock source as CPLD, and this clock source has very high frequency stability and precision, and frequency is 10MHz, uses by the frequency meter of supplying with after frequency multiplication in CPLD.Can avoid the unstable measuring error causing due to clock source.
3. realizing in high-precision measuring process, adopt after the sinusoidal signal and measured signal mixing that the DDS with following function is produced, the mode of measuring difference frequency improves the precision of measurement indirectly, make full use of measuring period method, high precision in the time that low frequency signal is measured, the ADE series frequency mixer that has adopted Mini-circuits to produce when mixing simultaneously, the distortion of mixer output signal is very little, has ensured the high precision of measuring.
The 4.CPLD features such as to have integrated level high for implementation, and volume is little, low in energy consumption that combine with single-chip microcomputer, are very suitable for being used in instrument and meter, and need to be used for weak this class measurement mechanism of magnetic detection system of caesium optical pumping of picture field geomagnetic field measuring.
Brief description of the drawings
Fig. 1 is the composition structured flowchart of the high precision testing circuit of caesium pumped magnetic resonance signal.
The digital frequency synthesizer that Fig. 2 is made up of CPLD form structural drawing block diagram.
The frequency meter that Fig. 3 is made up of CPLD form structural drawing block diagram.
Fig. 4 Single Chip Microcomputer (SCM) program process flow diagram.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the utility model is further described.
The high-precision detection device of the caesium pumped magnetic resonance signal that the utility model provides, its structure as shown in Figure 1, is mainly made up of high accuracy real-time clock, shaping circuit, mixting circuit, single-chip microcomputer, liquid crystal circuit, the frequency meter module being made up of CPLD and digital frequency synthesizer; Optical magnetic resonance signal to be measured, after shaping circuit is processed, is sent into the frequency meter module bigness scale of CPLD, and then single-chip microcomputer is according to the frequency of bigness scale, and signal of DDS module generation and the measured signal controlled in CPLD pass through mixting circuit mixing; Output difference frequency signal again after shaping circuit by the frequency meter module accurate measurement in CPLD, then by single-chip microcomputer, the processing such as the value of bigness scale and accurate measurement is added are just obtained to measured signal frequency accurately, finally give liquid crystal Circuit display.
The basic functional principle of whole device is as follows: optical magnetic resonance signal first to be measured is after low-pass filtering, convert to and be applicable to measuring square wave by limited range enlargement and shaping circuit again, then frequency meter 1 bigness scale of this square wave through being formed by CPLD, obtain the frequency values of an error in 10HZ, this frequency values is dealt into single-chip microcomputer by SPI mode by CPLD, single-chip microcomputer is received frequency data, intercept the above part of kilobit, generate a measured signal and differ the sinusoidal signal in 1KHz, then this signal and measured signal are by frequency mixer mixing, obtain the frequency difference signal of a frequency in 1kHz, this signal is after filtering, amplify and shaping, be sent to frequency meter 2, this frequency meter adopts the periodic mode work of surveying, measuring accuracy is very high, then the difference frequency data that record are mail to single-chip microcomputer, be added with the sinusoidal signal frequency of generation above, just can obtain the exact value of measured signal.
The digital frequency synthesizer that Fig. 2 is made up of CPLD form structural drawing.This digital frequency synthesizer is mainly made up of CPLD and MSP430 single-chip microcomputer, has good dynamic frequency following function.Frequency-tracking scope is at 50kHz to 1MHz, and frequency error is in 0.01Hz.In CPLD, mainly deposit is the phase accumulator of DDS, sine table, under the driving of the clock signal being provided by high-precision rubidium atomic clock source, outside, work, in single-chip microcomputer, main being responsible for produces corresponding frequency control word according to the frequency formula of DDS the frequency values that obtains in conjunction with bigness scale, and mails to CPLD and make it to produce and the sinusoidal signal of measured signal mixing.
The frequency meter module that Fig. 3 is made up of CPLD form structural drawing block diagram.Frequency in CPLD is in respect of two, and frequency meter 1, according to the work of frequency measurement ratio juris, is set to 1s gate time, and usage counter is recorded in the signal pulse number of passing through in 1s, in the time that arrive in gate time, exports this value zero clearing counter, prepares counting next time.Its object be mainly obtain one with the frequency values of measured signal error in 10Hz, this value will be addressed to single-chip microcomputer and be used for producing frequency control word.Frequency meter 2 is according to the principle work of measuring period method, with measured signal as signal strobe, be recorded in the pulse number of the known periods of passing through in gate time with counter, calculate frequency values accurately by single-chip microcomputer, the main task of this counter is the frequency values of Measurement accuracy difference frequency signal.Single-chip microcomputer is processed the data of these two counters accordingly, just can obtain the exact value of measured signal.
Fig. 4 Single Chip Microcomputer (SCM) program process flow diagram.After powering on, single-chip microcomputer is by SPI mode, the frequency values of reading frequency meter 1, then this frequency values is intercepted processing by single-chip microcomputer, obtain differing the frequency values in 1kHz with measured signal, obtain corresponding frequency control word by DDS frequency computation part formula and issue DDS, make the DDS sine wave output in CPLD.Then the difference frequency signal value of measuring by SPI mode reading frequency meter 2, a series of data processing of process just obtains the exact value of final measured signal.
Claims (2)
1. a high-precision detection device for caesium pumped magnetic resonance signal, is characterized in that this device is mainly made up of high accuracy real-time clock, shaping circuit, mixting circuit, single-chip microcomputer, liquid crystal circuit, the frequency meter module being made up of CPLD and digital frequency synthesizer; Optical magnetic resonance signal to be measured, after shaping circuit is processed, is sent into the frequency meter module bigness scale of CPLD, and then single-chip microcomputer is according to the frequency of bigness scale, and signal of DDS module generation and the measured signal controlled in CPLD pass through mixting circuit mixing; Output difference frequency signal again after shaping circuit by the frequency meter module accurate measurement in CPLD, then by single-chip microcomputer, the processing such as the value of bigness scale and accurate measurement is added are just obtained to measured signal frequency accurately, finally give liquid crystal Circuit display.
2. the high-precision detection device of caesium pumped magnetic resonance signal according to claim 1, is characterized in that communicating by SPI mode between described CPLD and single-chip microcomputer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320737198.2U CN203858351U (en) | 2013-11-20 | 2013-11-20 | High-precision detection device of magnetic resonance signal of cesium optical pump |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320737198.2U CN203858351U (en) | 2013-11-20 | 2013-11-20 | High-precision detection device of magnetic resonance signal of cesium optical pump |
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| CN203858351U true CN203858351U (en) | 2014-10-01 |
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| CN201320737198.2U Expired - Fee Related CN203858351U (en) | 2013-11-20 | 2013-11-20 | High-precision detection device of magnetic resonance signal of cesium optical pump |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106814249A (en) * | 2017-02-28 | 2017-06-09 | 中国科学院国家空间科学中心 | A kind of frequency measurement method for optical pumped magnetometer frequency meter |
| CN106842076A (en) * | 2017-03-08 | 2017-06-13 | 中国地质大学（武汉） | A kind of caesium optical pump signal automatic phase compensation system and method based on frequency-tracking |
| CN106885998A (en) * | 2017-03-08 | 2017-06-23 | 中国地质大学（武汉） | A kind of Method and circuits for improving caesium pumped magnetic resonance signal frequency-measurement accuracy and speed |
| CN113589035A (en) * | 2021-09-11 | 2021-11-02 | 北京芯同汇科技有限公司 | Frequency measuring device and measuring method |
| CN113848384A (en) * | 2021-09-22 | 2021-12-28 | 浙江大学 | High-precision feedback type frequency measuring device and method based on phase frequency detector |
-
2013
- 2013-11-20 CN CN201320737198.2U patent/CN203858351U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106814249A (en) * | 2017-02-28 | 2017-06-09 | 中国科学院国家空间科学中心 | A kind of frequency measurement method for optical pumped magnetometer frequency meter |
| CN106842076A (en) * | 2017-03-08 | 2017-06-13 | 中国地质大学（武汉） | A kind of caesium optical pump signal automatic phase compensation system and method based on frequency-tracking |
| CN106885998A (en) * | 2017-03-08 | 2017-06-23 | 中国地质大学（武汉） | A kind of Method and circuits for improving caesium pumped magnetic resonance signal frequency-measurement accuracy and speed |
| CN106842076B (en) * | 2017-03-08 | 2023-03-28 | 中国地质大学（武汉） | Frequency tracking-based automatic phase compensation system and method for cesium optical pump signals |
| CN106885998B (en) * | 2017-03-08 | 2023-07-11 | 中国地质大学（武汉） | Method and circuit for improving frequency measurement precision and speed of cesium optical pump magnetic resonance signals |
| CN113589035A (en) * | 2021-09-11 | 2021-11-02 | 北京芯同汇科技有限公司 | Frequency measuring device and measuring method |
| CN113848384A (en) * | 2021-09-22 | 2021-12-28 | 浙江大学 | High-precision feedback type frequency measuring device and method based on phase frequency detector |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141001 Termination date: 20171120 |